<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="https://cdn.bootcss.com/vue/2.6.10/vue.js"></script>
</head>

<body>
    <div id="app">
        <input type="text" v-model="keyword"><button @click="handleAdd">添加</button>
        <h4>历史记录</h4>
        <button v-for="item of historyWords.slice(0,4)">{{item}}</button>
    </div>
    <script>
        new Vue({
            el: "#app",
            data() {
                return {
                    msg: "hello world",
                    keyword: "",
                    historyWords: ["王妃", "你的名字"]
                }
            },
            methods: {
                handleAdd() {
                    // console.log("add")
                    if(!this.historyWords.includes(this.keyword)){
                        this.historyWords.unshift(this.keyword)
                    }
                }
            }
        })
    </script>
</body>

</html>